# Induction motor and sequence reactance

1. Jun 22, 2014

### honyeehong8692

Hello! This is my second post about sequence reactances. This time- its in induction motor.

To my understanding ( once again ) -

In any network (symmetrical or unsymmetrical) , there would be 3 components- positive sequence component, negative sequence component and zero sequence component.

Question:

In induction motors, what do the: running reactance, starter reactance and standstill reactance mean?

and,

Do any one of them signify/mean the positive sequence reactance of a unsymmetrical fault system?

2. Jun 22, 2014

### honyeehong8692

BTW, a prompt reply is very much appreciated. Please and thank you!

3. Jun 24, 2014

According to IEC 60909-0 Ch. 3.8 Asynchronous motors 3.8.1 General:
The impedance ZM = R M + jXM of asynchronous motors in the positive- and negative-sequence systems can be determined by:
ZM=1/(ILR/IrM)*UrM/sqrt(3)/IrM=UrM^2/SrM//(ILR/IrM)
Where
UrM is the rated voltage of the motor;
IrM is the rated current of the motor;
SrM is the rated apparent power of the motor (SrM = PrM/(effrM* COSfiTM);
PrM is the rated motor power [kW]
effrM is the rated motor efficiency
COSfiTM is the rated motor power factor
ILR/IrM is the ratio of the locked-rotor current to the rated current of the motor.